Dental treatment devices comprising silicone-like elastomeric material

ABSTRACT

Non-customized dental treatment trays used to provide a desired treatment are formed from elastomeric silicone or silicone-like material. They may be molded from a two-part liquid silicone composition or a silicone-like TPE material (e.g., preferably SEBS and/or VERSAflex thermoplastic elastomer). The dental treatment trays possess high adaptability, flexibility, softness, and elastic elongation while also exhibiting resiliency in order to readily conform to the ridges, depressions and contours of a person&#39;s teeth during use. The trays possess a greater ability to adhere to a person&#39;s teeth compared to non-elastomeric thermoplastic materials. Due to their high adaptability and conformability, the non-customized dental trays behave like a semi-custom dental tray when placed over conformed to a person&#39;s teeth, particularly when used in combination with a sticky, viscous treatment composition.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.14/303,029, filed Jun. 12, 2014, which is a continuation of U.S. patentapplication Ser. No. 13/074,485, filed Mar. 29, 2011, which is adivision of U.S. patent application Ser. No. 12/183,303, filed Jul. 31,2008, which claims the benefit of U.S. Provisional Application No.61/190,054, filed Aug. 31, 2007. The disclosures of the foregoingapplications are incorporated herein by reference in their entirety.

BACKGROUND OF THE INVENTION 1. The Field of the Invention

The present invention is in the field of shaped, flexible dental traysand strips used to deliver a dental bleaching composition to a person'steeth. More particularly, the invention relates to flexible dental traysand strips with enhanced user comfort and tooth adhesion.

2. The Relevant Technology

Virtually all people desire white or whiter teeth. A common bleachingmethod involves the use of a dental tray that is custom-fitted to aperson's teeth and that is therefore relatively comfortable to wear. Onetype of customized tray is made by vacuum forming a sheet of moistureresistant thermoplastic polymer material over a stone cast of a person'steeth, after which the custom tray may be cut out. Another is customizeddirectly using a person's teeth as a template (e.g., “boil-and-bite”trays). Non-customized trays that approximate the shapes and sizes of avariety of users' dental arches have also been used. A dental bleachingcomposition is placed into the tray and the tray placed over theperson's teeth for a desired period of time.

Another tooth bleaching method involves placing a flexible bleachingstrip over a user's tooth surfaces. Conventional bleaching stripscomprise a flexible plastic strip coated with a dental bleaching gel ofmoderate viscosity and relatively low stickiness on the side of thestrip facing the user's teeth. To install the bleaching strip, a portionof the bleaching strip is placed over the front surfaces of the user'steeth, and the remainder is folded around the occlusal edges of theteeth and against a portion of the lingual surfaces.

Because of the generally poor adhesion of bleaching strips to the user'steeth, coupled with their generally flimsy nature, it is often difficultfor the user to maintain the bleaching strip in its proper position forthe recommended time. Conventional bleaching strips are prone to slipoff the teeth as a result of even minimal movement of the user's mouth,jaw or tongue. It is recommended that the user not eat, drink, smoke orsleep while wearing the bleaching strip. In some cases, the bleachingstrip can become so dislodged or mangled that it must be removed by theuser and replaced with a fresh bleaching strip to complete therecommended bleaching time.

Ultimately, the main impediment to successful bleaching is the failureof users to complete the prescribed bleaching regimen. If the bleachingapparatus is difficult to install over a person's teeth, requiresnumerous repetitions to achieve observable results, and/or isuncomfortable to wear, the user may simply give up and prematurely abortthe prescribed bleaching regimen. Thus, even if dental bleaching ispossible using a particular bleaching apparatus or method, it is lesslikely to occur if the inadequacies of the bleaching apparatus or methodcause a user to become discouraged before desired results are attained.

BRIEF SUMMARY OF THE PREFERRED EMBODIMENTS

The present invention generally relates to improved dental treatmenttrays and strips used to deliver a dental treatment composition (e.g., adental bleaching composition) to a person's teeth. The inventive dentaltreatment trays and strips are formed from silicone or a material whichexhibits properties similar to silicone (e.g.,styrene-ethylene-butylene-styrene (SEBS), and/or VERSAflex, aproprietary thermoplastic elastomer alloy exhibiting elasticity andother properties similar to silicone. VERSAflex is sold by GLSCorporation, based in McHenry, Ill.). SEBS and VERSAflex arethermoplastic elastomers and may hereafter be referred to as “siliconelike materials”. These materials exhibit excellent adaptability,flexibility, elasticity, and softness, while also exhibiting resiliency(i.e., the ability to spring back once a force is released). Such acombination of properties translates into enhanced comfort during use bythe user. Because trays formed of silicone or silicone like materialsexhibit such beneficial characteristics even with relatively thick wallthicknesses, they have an added advantage of reduced flimsiness, makingthem easier to place. In other words, a silicone or silicone like dentaltreatment tray having a given wall thickness will exhibit adaptability,flexibility, and softness that is at least as good, and typicallysignificantly greater than, a thinner tray formed of more commonthermoplastic materials (e.g., EVA). In addition, the silicone tray willexhibit elasticity and excellent resiliency, which the more commonthermoplastic polymer materials tend to lack.

Silicone is both more comfortable and more adhesive to teeth andsurrounding oral tissues. Thus, it can be both more flexible compared toconventional tray and strip materials while more reliably remaining inplace over a person's teeth. Conventional strips are notoriouslynon-adhesive to teeth and readily slip off and/or become mangled inshort order. Silicone is also more resilient than conventional tray andstrip materials notwithstanding its also more flexible and comfortable,which further helps it maintain itself in the correct orientation over aperson's teeth.

Such silicone and silicone like trays and strips even have improvedcharacteristics relative to trays and strips made from thermoplasticmaterials which also include a significant fraction of one or moreplasticizers (e.g., mineral oil, paraffin oil, paraffin wax, petrolatum,liquid petrolatum, and/or nujol), which is really an attempt to mimicsilicone like qualities with more common thermoplastic polymermaterials. Although silicone raw materials may be significantly moreexpensive than the commonly thermoplastic polymer materials (e.g., EVA,PCL, PVC, PP, PE, polyesters, polycarbonates, polyamides, polyurethanes,and polyesteramides), the inventors' practical experience has shown thatlabor costs in manufacturing relatively comfortable thin wall (e.g.,less than about 0.4 mm) dental treatment trays from plasticizedthermoplastic materials are so significant, that a cost savings andimproved tray characteristics may be realized by forming the trays fromsilicone or a silicone like material instead. Similar advantages areassociated with strips formed of silicone.

When using silicone, it is not necessary to mix the forming materialwith other components. According to one such embodiment, the dental trayis formed of a material consisting essentially or even solely ofsilicone. The ability to eliminate the need for additional materialsgreatly simplifies manufacture, as only the silicone material (e.g.,provided as a medical grade thermoset two-part liquid composition) isneeded.

As SEBS and VERSAflex are thermoplastic materials, it may be easier tomix additional components with these materials so that the dental trayis formed of SEBS and/or VERSAflex, although any such additionalmaterials are preferably included in small amounts (e.g., no more thanabout 10% by weight, more preferably not more than 5% by weight, morepreferably not more than 3% by weight, even more preferably not morethan 1% by weight), as the best results have been found when the formingmaterial consists essentially of silicone or a silicone like material.

The silicone dental trays and strips are characterized by wallthicknesses of no more than about 1 mm, typically between about 0.03 mmand about 1 mm, more typically between about 0.1 mm and about 0.5 mm.Wall thicknesses greater than about 1 mm have little or no use as acomfortable dental tray or strip, as the thickness of the tray or stripbegins to interfere with the normal relaxed position of the occlusaltooth surfaces when wearing such a tray or strip, and otherwise makingthe tray or strip significantly less comfortable than a tray or stripwith a wall thickness that is no more than about 1 mm. For example thetray(s) get in the way between oppositely disposed teeth, preventing theuser from completely closing their jaw, and the overall bulk of the traybecomes very noticeable and uncomfortable within the user's mouth.

The durometer hardness/softness of the silicone or silicone likematerial is selected so as to strike a balance between softness and wallthickness. Within the preferred wall thicknesses described above (i.e.,about 0.03 mm to about 1 mm) the shore A durometer hardness value willpreferably range from about 90 to about 20. Generally, higher durometervalues (less softness) are preferred with thinner wall trays, whilelower durometer values (greater softness) are preferred with thickerwall trays. For example, a tray with a wall thickness of about 0.25 mmmay advantageously have a shore A durometer hardness value of about 40,while a tray with a wall thickness of about 0.1 mm may have a shore Adurometer hardness value of about 70.

In one example, the treatment tray is configured so as to include abuccal-labial side wall (i.e., a front side wall) and a bottom walladjacent the buccal-labial wall so as to have an approximately L-shapedcross section. Alternatively, the tray may also include a lingual sidewall (i.e., a rear side wall) which extends laterally from an oppositeside of the bottom wall such that the tray has an approximately U-shapedcross section.

The dental treatment trays may be either custom or non-custom. In otherwords, silicone or a silicone like material may be used to form a customdental tray designed to fit the unique size, shape, and overalldentition of an individual's upper or lower dental arch. Typically apair of trays is custom formed, one for the upper dental arch and onefor the lower dental arch. Such trays may typically be formed over astone cast representing the unique dental arch of a single user. As SEBSand VERSAflex are thermoplastic materials, they may be preferredmaterials for use in forming a custom dental tray, as they may bethermoformed over a stone cast.

In the case of a non-custom dental tray, the tray is pre-formed duringmanufacture so as to be substantially devoid of structures correspondingto the size and shape of a person's unique dentition so that the tray isdesigned to comfortably fit over a plurality of differently-sized and/orshaped teeth corresponding to different people. Such a non-custom traymay be pre-loaded with a dental treatment composition. The treatmentcomposition may comprise a sticky viscous gel, a less viscous gel, ahighly viscous putty, or a substantially solid composition that is lessadhesive prior to being moistened with saliva or water but that becomesmore sticky and adhesive when moistened.

The size and shape of such non-custom trays (or non-custom strips)according to the invention can be tailored to readily fit a person'supper or lower dental arch. The treatment trays and strips may come invarious sizes (e.g., small, medium and large) to better adapt todifferently-sized dental arches and/or teeth among the population atlarge. The dental treatment trays and strips are advantageously designedso as to substantially cover the front and lingual surfaces of the teethand/or gums to be treated.

According to one embodiment, relatively thin dental treatment trays orstrips (e.g., having wall thicknesses less than about 0.4 mm) may beused in combination with a supporting structure, such as an outersupport tray, prior to use. An outer support tray is particularly usefulwhen the dental tray or strip is so thin and flexible (i.e., somewhatflimsy) as to be difficult to place over a person's teeth without theside wall(s) collapsing inwardly. As described above, the durometerhardness of the silicone or silicone like material will preferably besomewhat higher with such thin-wall trays and strips in order to reducetheir tendency to collapse inwardly. The outer support tray may have thesame configuration as the treatment tray so as to receive and supportthe treatment tray in a nesting fashion. In one embodiment, the outersupport tray includes a handle to facilitate gripping andmaneuverability of the outer support tray while placing the treatmenttray over the teeth. Once positioned, the outer support tray can beremoved so as to leave the treatment tray in place over the teeth.

Of course, silicone or silicone like dental trays and strips mayadvantageously be formed with sufficient wall thickness (e.g., at leastabout 0.45 mm) so that they exhibit sufficient self-supporting integrity(i.e., they are not so flimsy that the side wall(s) collapse inwardly)so that no outer support tray or other supporting structure is required.Such relatively thick trays advantageously exhibit excellentadaptability, resiliency, softness, flexibility, and comfort which isgreater than a similarly sized tray formed of, for example an EVA/PP andplasticizer blend.

These and other advantages and features of the present invention willbecome more fully apparent from the following description and appendedclaims, or may be learned by the practice of the invention as set forthhereinafter.

BRIEF DESCRIPTION OF THE DRAWINGS

To further clarify the above and other advantages and features of thepresent invention, a more particular description of the invention willbe rendered by references to specific embodiments thereof, which areillustrated in the appended drawings. It is appreciated that thesedrawings depict only typical embodiments of the invention and aretherefore not to be considered limiting of its scope. The invention willbe described and explained with additional specificity and detailthrough the use of the accompanying drawings in which:

FIG. 1 is a perspective view of an exemplary non-custom dental treatmenttray according to the invention;

FIG. 2A is an exploded view of a dental treatment tray having anatomicalfeatures to improve fit and an optional complementary outer supporttray;

FIG. 2B is a perspective view showing the dental treatment tray nestedwithin the outer support tray;

FIG. 3 is a perspective view of an exemplary dental treatment stripaccording to the present invention;

FIG. 4 illustrates a pair of pre-filled tray assemblies similar to theassembly of FIG. 2B contained within a sealed protective package havinga peelable cover;

FIG. 5 is a cross-sectional view of a tray assembly including arupturable membrane between the barrier layer and the treatmentcomposition;

FIG. 6A illustrates a person placing a dental treatment tray accordingto the invention over the person's upper dental arch; and

FIG. 6B illustrates dental treatment trays according to the invention inplace over both the upper and lower dental arches.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS I. Introduction

The present invention relates to silicone or silicone like dentaltreatment trays and strips used to deliver a dental treatmentcomposition to a person's teeth. Surprisingly, forming the trays andstrips from silicone or a silicone like material is able to provide bothbetter adaptability (i.e., the ability of a non-custom tray to be shapedand adapted to conform to the user's dental arch) as compared to morecommonly used materials (e.g., EVA), while also providing increasedresiliency (i.e., the ability of the tray structure to spring back intoplace), which unique combination of properties (adaptability andresiliency) is counterintuitive and surprising. Because trays and stripsformed of silicone or a silicone like material exhibit suchcharacteristics even with relatively thick wall thicknesses (e.g.,between about 0.45 mm and about 1 mm), when formed with suchthicknesses, they have an added advantage of reduced flimsiness, makingthem easier to place (i.e., no outer support tray is required). In otherwords, a silicone or silicone like dental treatment tray or strip havinga given wall thickness will exhibit adaptability, flexibility, andsoftness that is at least as good, and typically significantly greaterthan, a thinner tray or strip formed of more common thermoplasticmaterials (e.g., EVA). In addition, the silicone or silicone like dentaltray or strip exhibits excellent resiliency and elasticity, whichqualities are often lacking in trays and strips formed of othermaterials. The unique combination of properties increases the comfort tothe user, which might be expected to increase compliance with a giventreatment regimen.

II. Exemplary Silicone or Silicone Like Dental Trays

FIG. 1 illustrates an exemplary non-custom dental tray 100 which isformed by liquid injection molding a silicone or silicone like material.For example, a silicone material may initially comprise a two-partcomposition including a first part comprising one or more siloxanes anda second part including an activator. Upon mixing the two liquid partstogether, the siloxane(s) polymerizes and cross-links so as to form apolysiloxane. Heat may be applied (e.g., by heating the mold) toaccelerate polymerization of the silicone material. For example, part Aand part B of the raw silicone material are mixed together, which causesthe silicone to begin to polymerize. For many exemplary siliconematerials, this reaction could take 2-6 weeks to completely cure at roomtemperature. Heating the mixture significantly increases the rate atwhich the material polymerizes. For example, according to one method,the material is heated to 375° F. so as to cause the material topolymerize in a matter of seconds. Actual polymerization time depends onthe thickness of the tray or strip being formed. The inventive traysand/or strips may also be formed by other methods, for example in whicha two part silicone in which polymerization is activated by mixingand/or by compression.

Dental treatment tray 100 includes a shaped tray body 102. The shapedtray body 102 includes a buccal-labial front side wall 104, a lingualrear side wall 106, and a bottom wall 108 bridging the buccal-labialwall 104 and buccal-labial wall 106. Bottom wall 108 is adjacent tobuccal-labial wall 104 such that buccal-labial wall 104 extendslaterally from bottom wall 108 in a substantially vertical direction.Buccal-labial wall 104 is shown as including an optional v-shaped cut105 formed along the top surface thereof, near the center where theincisors reside during use. Such a cut helps wall 104 to stretch andflex so as to better accommodate the incisors. Although not shown, sucha similar cut or discontinuity may be formed within lingual wall 106.Lingual wall 106 is disposed at the opposite side of bottom wall 108,extending laterally upwardly and outwardly therefrom. The buccal-labialwall 104, lingual wall 106, and bottom wall 108 together form a shapedtray body 102 having an approximate U-shaped cross section and agenerally horseshoe-shaped curvature.

The size, shape and curvature of the shaped tray body 102 areadvantageously selected in order for the horseshoe-shaped curvature togenerally approximate the curvature of a person's dental arch. TheU-shaped cross section generally corresponds to and defines an interiorcavity of the tray body 102. The depth of the interior cavity isselected in order for the buccal-labial and lingual walls 104 and 106respectively to extend over a desired portion of a person's teeth, andoptionally, over a portion of the person's gums. Because of theexcellent adaptability, flexibility, elasticity, and resiliency affordedby the silicone or silicone like material from which shaped tray body102 is formed, the ability of buccal-labial wall 104, lingual wall 106,and bottom wall 108 to conform and adapt to a person's teeth isincreased relative to trays formed of other materials.

Because of its non-custom nature (i.e., tray shaped body 102 issubstantially devoid of structures corresponding to the size and shapeof a person's unique dentition), the tray shaped barrier layer body 102comfortably fits over a plurality of differently sized and/or shapedteeth corresponding to different people. Nevertheless, it is within thescope of the invention to provide separate dental trays that are sizedand configured to correspond to either a person's upper or lower dentalarch, as the lower dental arch is typically smaller than the upper arch,with lower teeth that are typically smaller than the upper teeth. It isalso within the scope of the invention to provide varyingly-sizedbleaching trays to account for variability among different people'sdental arches and/or teeth (e.g., adults versus children, larger mouthsversus average or smaller mouths, and larger teeth versus average orsmaller teeth).

The tray body 102 may be injection molded, vacuum formed, cut and/orstamped from a sheet of polymeric material, although injection moldingis preferred over methods that involve cutting and/or stamping becausethe outer edges 109 of each wall may be injection molded so as to have asmooth, rounded edge surface as opposed to the sharp, angled surfacesformed when a tray is cut or stamped from a sheet of material. Suchsmooth edges also contribute to the overall comfortable feel of thetray.

Tray 100 includes an inner treatment surface 103 that includes theinwardly oriented surfaces of buccal-labial front side wall 104, bottomwall 108, and lingual rear side wall 106 that will be positioned againsttooth tissue to be bleached during use. At least a portion of innersurface 103 may include one or more bleaching agent destabilizers. Inone embodiment, the destabilizer may be compounded with the moistureresistant (e.g., polymeric) material from which the tray 100 is formed.In such an example, the destabilizer is distributed substantially evenlythroughout the material from which tray 100 is formed, so that at leastsome destabilizer is present on inner treatment surface 103. In anotherembodiment, the destabilizer may be applied to at least a portion ofinner surface 103, for example, by spraying, brushing, or otherwiseapplying the destabilizer onto the inner treatment surface 103.Advantageously, the destabilizer may be present on at least that portionof inner surface 103 corresponding to surfaces of the teeth to bebleached. For example, the destabilizer may be present on at least thelower portion of buccal-labial front side wall 104 nearest bottom wall108, which corresponds to the labial surface of the teeth to bebleached. Destabilizers may advantageously be absent from any portionsof the tray designed to contact gingival tissue, where no bleaching isto take place.

The one or more bleaching agent destabilizers act to destabilize theperoxide dental bleaching agent during use. When peroxides aredestabilized they more rapidly release free radicals, which cause toothbleaching. For example, it is believed that peroxide dental bleachingagents are destabilized to form predominantly hydroxyl (HO.) freeradicals, although peroxyl (.OOH), super oxide (.O), and super dioxide(.OO) free radicals may also be formed. Upon decomposition, which isaccelerated by the bleaching agent destabilizer, these free radicals aremore easily able to pass into the tooth enamel to the location of toothstains as compared to the larger peroxide (H₂O₂) molecules, which mayhave increased difficulty passing through tight spaces of the enamel tostain locations because of their larger size. The bleaching agentdestabilizer is advantageously retained on at least inner treatmentsurface 103 of the tray or strip prior to use, and upon contact with aperoxide dental bleaching agent in the presence of water; thedestabilizer becomes activated, resulting in formation of free radicalsfrom the peroxide for increased bleaching effect.

One class of bleaching agent destabilizers includes transition and/oralkaline earth metal ions. Non-limiting examples of suitable metal ionsinclude magnesium ions, iron ions, titanium ions, cobalt ions, nickelions, copper ions, platinum ions, tin ions, zinc ions, manganese ions,chromium ions, silver ions, aluminum ions, and combinations thereof.Magnesium and/or iron ions are particularly preferred. Another class ofbleaching agent destabilizer includes enzymes, particularlyorgano-metallic enzymes containing transition metals, such as iron.Examples include “peroxidase” and “catalase”, which is described moreparticularly in U.S. Pat. No. 6,485,709 to Banerjee et al., hereinincorporated by reference with respect to its disclosure oforgano-metallic enzymes.

One or more bleaching agent destabilizers including the above metal ionsin available form and/or organo-metallic enzymes are preferablycollectively included in an amount in a range of about 0.01% to about20% by weight of the polymeric material, more preferably in a range ofabout 0.05% to about 10% by weight, and most preferably about 0.1% toabout 5% by weight. Examples of suitable metal compounds includeiodides, nitrates, chlorates, borates, perchlorates, and perborates ofsuitable metal cations. Preferred specific compounds include MgO, ferricsulfate, ferric chloride, MnO₂, and TiO₂. Less preferred bleaching agentdestabilizers include elemental metals (e.g., iron, silver, platinum,copper, magnesium, titanium, cobalt, nickel, tin, zinc, chromium,aluminum, and/or manganese in powder form). Of course, any other metalions mentioned herein may also be used in elemental form. Another classof bleaching agent destabilizers that may be used include iodine salts(e.g., potassium iodide and/or sodium iodide).

Many of the metal ion containing compounds are believed to react withthe peroxide bleaching agent according to Fenton's Reaction, forexample, ferric Fe²⁺ ions react to form ferrous Fe³⁺ ions in thepresence of peroxide, releasing oxygen free radicals. During the courseof the reaction, the peroxide is regenerated, allowing more ferric ionsto react, resulting in production of more oxygen free radicals.

FIG. 2A illustrates an alternative non-custom dental treatment tray 200including a shaped tray body 202 that may be liquid injection moldedfrom a two-part silicone material or injection molded from a siliconelike TPE material. The adaptability and elasticity of the silicone orsilicone like material allows such a non-custom tray to more closelyconform and adapt to the person's dental arch, with excellent comfort.Tray 200 includes anatomical structural features that allow tray 200 tomore closely conform to a person's teeth during use. Body 202 includes abuccal-labial front side wall 204, a bottom wall 208, and a lingual sidewall 206 connected to bottom wall 208 at an opposite side relative tobuccal-labial wall 204. An inner treatment surface 203 is defined byinterior portions of bottom wall 208, buccal-labial front side wall 204,and lingual side wall 206. Illustrated tray 200 is sized and configuredfor placement over a person's upper dental arch. As illustrated, lingualwall 206 may advantageously include a notch 205, which allows thenon-custom tray 200 to more easily spread open or compress in the areaof the incisors. This is helpful in allowing the lingual wall 206 of thenon-custom tray 200 to more easily conform to differently-sized dentalarches. Bottom wall 204 includes an abrupt reduction in width positionedat locations 210 corresponding to a transition between posterior teeth(i.e., bicuspids and molars) and anterior teeth (i.e., canines andincisors). Bottom wall 208 also advantageously includes two v-shapedindentations 216 for insertion into the depression between the occlusalpeaks of the posterior teeth (i.e., the bicuspids and molars).

Similar to tray 100, at least a portion of inner surface 203 of tray 200may include one or more bleaching agent destabilizers. In a preferredexample, the one or more dental bleaching agent destabilizers may becompounded with the moisture resistant polymeric material from which thetray 200 is formed. In such an example, the destabilizers may bedistributed substantially evenly throughout the material from which tray200 is formed, so that at least some destabilizer is present on innertreatment surface 203. Alternatively, one or more bleaching agentdestabilizers may be applied (e.g., after molding or otherwise formingtray body 202) to at least a portion of inner treatment surface 203where dental bleaching composition will be applied during use, and whichsurfaces of the tray will be placed against tooth tissues to be bleachedduring use.

FIG. 2A is an exploded view showing the dental treatment tray 200 incombination with a corresponding optional outer support tray 250 that iscomplementarily shaped so as to be capable of receiving the dentaltreatment tray 200 in a nested configuration (see FIG. 2B). The outersupport tray 250 may include the same anatomical features as tray 200 inorder to provide a closer fit. The outer support tray 250 advantageouslyincludes a handle 252 extending outwardly from a central portion of thebuccal-labial front wall in order to facilitate gripping by the userduring placement of the dental bleaching tray 200 over the person'steeth.

In FIG. 2B, dental treatment tray 200 is nested within outer supporttray 250 so as to form a dental tray assembly 255. The handle 252extends beyond the buccal-labial wall of tray 200 in order to facilitateplacement and removal of the outer support tray 250 after placement oftray 200 over the person's teeth.

FIG. 3 illustrates an exemplary dental treatment strip 400 which isformed from a polymeric material. Strip 400 is advantageously formedfrom silicone or a silicone like material. Silicone is both morecomfortable and more adhesive to teeth and surrounding oral tissues ascompared to materials currently used to manufacture dental strips (e.g.,EVA). Thus, it can be both more flexible compared to conventional stripmaterials while more reliably remaining in place over a person's teeth.Conventional strips are notoriously non-adhesive to teeth and readilyslip off and/or become mangled in short order. As such, strips formed ofsilicone or a silicone like material provide both better adaptability(i.e., the ability of a non-custom strip to be shaped and adapted toconform to the user's dental arch) as compared to more commonly usedmaterials (e.g., EVA), while also providing increased adhesiveness(i.e., the ability of the strip material itself to grip or adhere totooth tissue). Strips are generally formed so as to be relatively thin(e.g., between about 0.03 mm and about 1 mm, more typically betweenabout 0.1 and about 0.5 mm).

The inventors have found that given these thicknesses and the strip'sshape, the resilient nature of the silicone (which is advantageous intray structures) is overshadowed by the adhesive, grippingcharacteristics of the material. In other words, relatively thin stripsof silicone do not exhibit shape memory resiliency to a degree thatmight otherwise cause the silicone strip to not adhere to the toothsurfaces once folded over. Rather, the adhesive, grippingcharacteristics of the silicone material, in addition to theadhesiveness of the bleaching composition, hold the strip in place. Thisadhesive, gripping characteristic (which appears to be a surfacephenomenon of the material) is also present in trays formed of siliconeand silicone like materials, which helps the material grip and adhere totooth tissue

Dental treatment strip 400 is initially substantially rectangular andincludes a planar surface 402 which can be positioned adjacent the teethto be bleached and folded along the incisal edge of the teeth so as tocover the labial and incisal tooth surfaces. Depending on the positionof the fold during placement, a portion (or substantially all) of thelingual tooth surfaces may also be covered by the strip 400 once placed.At least a portion of planar surface 402 defines an inner treatmentsurface corresponding to portions of surface 402 which are positionedadjacent to particularly the labial teeth surfaces during use.

At least a portion of inner planar surface 402 oriented toward aperson's tooth surfaces may include one or more bleaching agentdestabilizers. In a preferred example, the one or more dental bleachingagent destabilizers may be compounded with the moisture resistantpolymeric material from which the strip 400 is formed. In such anexample, the destabilizers may be distributed substantially evenlythroughout the material from which strip 400 is formed, so that at leastsome destabilizer is present on planar treatment surface 402.Alternatively, one or more bleaching agent destabilizers may be applied(e.g., after forming of strip barrier layer 400) to at least a portionof inner treatment planar surface 402 where dental bleaching compositionwill be applied during use and which surfaces of the strip will beplaced against tooth tissues to be bleached during use.

Although conventional strips are less effective in treating teethrelative to tray shaped barrier layers because strips tend to readilyslip off and/or become mangled before treatment is complete, an improveddental treatment strip can be provided according to the presentinvention by providing a bleaching agent destabilizer compounded withinor otherwise disposed on an inner treatment surface of the strip. Suchstrips may provide for improved bleaching as the destabilizer acts topromote formation of active bleaching free radicals from the peroxidebleaching agent, which may be expected to result in faster bleaching, atleast partially counteracting the disadvantages (i.e., tendency to slipoff and/or mangle) of strips.

Any silicone or silicone like dental tray or strip according to theinvention may be provided separately from a dental treatmentcomposition, which is introduced into the tray (e.g., adjacent thetray's inner treatment surface) or applied onto the strip by the userimmediately prior to use. In one alternative embodiment, it may bepossible to prefill a tray or preapply a dental bleaching composition toa strip if the bleaching composition is anhydrous. The anhydrous dentalbleaching composition may be disposed directly in contact with thebarrier layer, and will not react prematurely because of the anhydrousnature of the bleaching composition. As soon as water is added to thesystem (e.g., when contacted by saliva by placing the pre-filled tray orpre-applied strip on the teeth), reaction between the destabilizer andbleaching agent will begin. Embodiments including an anhydrous dentalbleaching composition may advantageously be sealed within a protectivepackage to prevent absorption of water from the surrounding air duringshipment and storage.

Another alternative embodiment may include an anhydrous adhesivecomposition (e.g., including polyvinyl pyrollidone as an adhesive agent)that also includes a bleaching agent destabilizer (e.g., potassiumiodide). The adhesive destabilizing composition may be coated over thebarrier layer (e.g., as a thin layer or film). It is important to notethat such a composition including the bleaching agent destabilizer isapplied to a region of the barrier layer corresponding to the toothsurfaces to be bleached. In other words, if the composition is notapplied over substantially the entire interior surface of the barrierlayer tray or strip, it is at least applied to that portion of thebarrier layer which in use is positioned against the tooth surfaces tobe bleached (e.g., at least the labial tooth surface). It is notnecessary to apply the bleaching agent destabilizer to regions of thebarrier layer which will be positioned against gum tissue during use. Infact it may be preferable in some embodiments to ensure that nobleaching agent destabilizer is present in regions of the barrier layerwhich will be positioned against gingival tissue so as to preventreaction with peroxide bleaching agents adjacent the gingival tissue,which may otherwise cause discomfort and soreness. Of course, inembodiments where the destabilizer is compounded within the material ofthe barrier layer this may be impractical, although discomfort togingival tissues may be prevented by limiting application of thebleaching composition to regions of the barrier layer corresponding totooth surfaces to be bleached.

In other words, it may be preferred to apply the bleaching compositionso that substantially no bleaching composition is applied adjacent anypart of the barrier layer that will be positioned adjacent the gingivaltissue, so that the bleaching agent and the destabilizer are onlypresent together at portions of the tray corresponding to tooth surfacesto be bleached. In embodiments where the destabilizer is applied as afilm or composition layer, it may be preferable to maintain any portionsof the barrier layer which will be positioned adjacent to gingivaltissue so that they are substantially free of the bleaching agentdestabilizers, and that the destabilizer film or layer is only appliedto those portions of the barrier layer corresponding to tooth surfacesto be bleached (e.g., at least the labial tooth surface). In otherwords, in any embodiment, the bleaching agent and the destabilizer maybe present together only at those portions of the tray corresponding totooth surfaces to be bleached. At portions of the tray that will bepositioned adjacent to gingival tissue during use, only one or the other(or neither) of the bleaching agent destabilizer and the bleaching agentare present so as to prevent discomfort and soreness.

In embodiments where the adhesive destabilizer composition is anhydrous,a peroxide bleaching agent may also be included, so long as no water ispresent so as to prevent premature reaction between the bleaching agentdestabilizer and the peroxide bleaching agent. Alternatively, ableaching composition (e.g., an aqueous gel) may be applied over thelayer or film adhesive layer just prior to use. The water within thebleaching composition and/or saliva within the user's mouth causes thebleaching agent destabilizer to be activated in the presence of thebleaching agent.

In another alternative embodiment, a non-custom dental tray or stripaccording to the invention may be preloaded with a dental bleachingcomposition. In order to prevent premature contact between the bleachingagent destabilizer and bleaching composition, the tray or strip furtherincludes a protective rupturable membrane disposed between the barrierlayer and the bleaching composition. The membrane may be configured tobe rupturable subsequent to placement of the tray over the person'steeth. For example, a rupturable membrane of a tray or strip bleachingdevice may be configured to rupture upon biting, bending and/or foldingof the barrier layer and membrane. Such a rupturable membrane maycomprise any rupturable layer that is disposed between the bleachingcomposition and the tray or strip including a bleaching agentdestabilizer. Examples of suitable materials include a protectivecoating layer of high molecular weight polyethylene glycol, adi-para-xylene coating layer, and/or a wax coating. Di-para-xylene isavailable commercially as Parylene from Parylene Coating Services, Inc.,located in Katy, Tex. Such coatings may serve to simply separate thebleaching composition from the barrier layer during storage andshipment, and the coating membrane is ruptured upon biting, bending,and/or flexing of the tray or strip. The rupturable membrane layer maybe water-degradable so as to dissolve, degrade, or become dispersed uponcontact with moisture (e.g., saliva).

Such a tray or strip may be provided within a sealed container orpackage to protect the tray or strip, the treatment composition, andrupturable membrane from contaminants and/or premature rupture duringstorage, transport, and prior to use. FIG. 4 shows a first tray assembly355 configured for placement over an upper dental arch and a second trayassembly 355′ configured for placement over a lower dental arch sealedwithin protective package 356. Each tray 300 and 300′ includes atreatment composition 354 pre-loaded therein. Protective package 356includes a rigid support layer 358 and a peelable cover 360. Each trayassembly 355 and 355′ may optionally include an additional removableprotective layer (not shown) placed adjacent to the treatmentcomposition 354 for additional protection. When it is desired to use thedental treatment tray devices, the peelable cover 360 is removed and thetray assemblies 355 and 355′ are removed or separated from support layer358.

FIG. 5 illustrates a cross-sectional view through tray assembly 355 ofFIG. 4, including tray 300 and outer support tray 350, perhaps bestillustrating protective rupturable membrane 357 disposed adjacent toinner treatment surface 303 of tray 300.

Another embodiment may include a multi-use tray, for example a customdental tray formed by vacuum forming a sheet of moisture resistantthermoplastic polymer material over a stone cast of a person's teeth,after which the custom tray may be cut out. Such custom trays can bevery comfortable to wear as they provide an excellent fit to the user'sdentition. A bleaching agent destabilizer (e.g., a ferric salt) may becompounded with the tray material or otherwise provided so that thebleaching agent destabilizer is present on the interior treatmentsurface of the tray. During use, the user applies a bleachingcomposition into the tray, and then places the tray over the teeth forbleaching treatment. The bleaching agent destabilizer, for example, aferric salt, is oxidized during use so as to form ferrous ions. Becauseat least some of the bleaching agent destabilizer will likely remainafter use, the custom tray may be used multiple times before all thebleaching agent destabilizer has been consumed. Once all bleaching agentdestabilizer has been consumed, the custom tray may still be used as aconventional custom bleaching tray, although it will no longer providethe increased bleaching effect afforded by the bleaching agentdestabilizer.

The trays and strips may be used with any known dental treatmentcomposition. Examples of treatment compositions include dental bleachingcompositions (e.g., including a dental bleaching agent such as aperoxide), desensitizing compositions (e.g., including a desensitizingagent such as potassium nitrate, other potassium salts, citric acid,citrates, and/or sodium fluoride), remineralizing compositions (e.g.,including a remineralizing agent such as sodium fluoride, stannousfluoride, sodium monofluorophosphate, and/or other fluoride salts),antimicrobial compositions (e.g., including an antimicrobial agent suchas chlorhexidine, troclosan, and/or tetracycline), antiplaquecompositions, and anti-tartar compositions (e.g., including ananti-tartar agent such as a pyrophosphate salt). The treatmentcomposition may comprise a sticky viscous gel, a less viscous gel, ahighly viscous putty, or a substantially solid composition that is lessadhesive prior to being moistened with saliva or water but that becomesmore sticky and adhesive when moistened

According to one embodiment, the barrier layer comprises a thin (e.g.,about 1 mm or less), flexible membrane formed from a polymeric or othermoisture-resistant material. Polymeric materials are preferred. In oneembodiment, the barrier layer comprises silicone. In another, itcomprises ethyl vinyl acetate and polypropylene. According to anotherembodiment, it may be formed of a polyolefin or similarlymoisture-resistant material, such as wax, paraffin, ethylene-vinylacetate copolymer (EVA), ethylene-vinyl alcohol copolymer (EVAL),polycaprolactone (PCL), polyvinyl chloride (PVC), polyesters,polycarbonates, polyamides, polyurethanes or polyesteramides. Examplesof suitable polyolefins for use in making the barrier layer include, butare not limited to, polyethylene (PE), high density polyethylene (HDPE),low density polyethylene (LDPE), ultra low density polyethylene (ULDPE),polypropylene, and polytetrafluoroethylene (PTFE) (e.g., TEFLON). Anexample of a suitable polyester for use in making the barrier layerincludes, but is not limited to, polyethylene terephthalate (PET), anexample of which is MYLAR, sold by DuPont. An example of a suitablepolyurethane barrier material is a polyurethane film manufactured byArgoTech, which is located in Greenfield, Mass. The barrier layer maycomprise a polymeric blend and/or multiple layers comprising two or moreof the foregoing materials. Plasticizers, flow additives, and fillersknown in the art can be used as desired to modify the properties of anyof the foregoing polymers used to form the barrier layer. The forgoinglisting of polymeric materials is not meant to be exhaustive, asnumerous other polymeric materials may be used.

Other materials that can act as a barrier layer include metal foil,cellulosic ethers, cellulose acetate, polyvinyl acetate, polyvinylalcohol, shellac, and chemical or light-cure materials (e.g.,methacrylate or acrylate resins). Examples of useful cellulosic ethersthat can be used to form a barrier layer include, but are not limitedto, ethyl cellulose, propyl cellulose, isopropyl cellulose, butylcellulose, t-butyl cellulose, and the like. Although non-polymericmoisture resistant materials, e.g., metal foil, may be used, polymericmaterials are preferred.

Advantageously, the tray or strip consists essentially of silicone or asilicone like material, as this has been found by the inventors toprovide the most beneficial combination of properties, includingexcellent adaptability, flexibility, softness, and elasticity, whilealso exhibiting excellent resiliency. Although it is preferred that themoisture resistant polymer material of the tray or strip body consistsolely of silicone or one or more silicone like materials, it may bepossible in some embodiments to include additional moisture resistantpolymer components so that the material comprises a blend ofsilicone/silicone like materials and other materials. Additionalmaterials that may be included in such an example include one or moreelastomers (e.g., a non-silicone like thermoplastic elastomer), latexes,and/or nitriles. Preferably any such additional moisture resistantcomponents comprise no more than about 10% by weight of the tray, morepreferably no more than about 5%, and most preferably no more than about3% by weight. Additional components such as water and/or a plasticizer(e.g., PEG), a colorant, and/or a flavorant may be added to thecomposition from which the tray or strip body is formed.

Exemplary suitable two-part silicone materials are available fromShin-Etsu Silicones of America, located in Akron, Ohio. One preferredmaterial is KEG2000-50A/B, the physical properties of which aredescribed in the table below. Various other Shin-Etsu silicone productsand silicone materials from other suppliers can also be used.

Property Value Hardness-Shore-A 52 Tensile Strength-MPa 11.1Elongation-% 580 100% Modulus-Mpa 1.72 Tear Strength-kN/m 40 Comp Set 22h/302° F.-1 h/302° F. 31 Comp Set 22 h/302° F.-4 h/392° F. 8 LinearShrinkage 2.6 Specific Gravity 1.13 Viscosity-Part A-Pa · s 1700Viscosity-Part B-Pa · s 1600

For example, a silicone material may initially comprise a two-partcomposition including a first part comprising one or more siloxanes anda second part including an activator. Upon mixing the two liquid partstogether, the siloxane molecules polymerize and cross-link so as to forma polysiloxane. Heat may be applied (e.g., by heating the mold) toaccelerate polymerization of the silicone material. For example, part Aand part B of the raw silicone precursor material are mixed together,which causes the material to begin to polymerize. For many exemplarysilicone materials, this reaction could take 2-6 weeks to completelycure at room temperature. Heating the mixture significantly increasesthe rate at which the material polymerizes. For example, according toone method, the material is heated to 375° F. so as to cause thematerial to polymerize in a matter of seconds. Actual polymerizationtime depends on the thickness of the tray or strip being formed.Silicone trays and/or strips may also be formed by other methods, forexample with a two part silicone in which polymerization is activated bymixing and/or by compression.

Silicone polymeric materials include a platinum and/or tin catalystwithin one or both parts of the composition to assist withpolymerization. Advantageously, residual catalyst is present within thematerial after the tray or strip has been formed. Residual platinumand/or tin catalyst disposed throughout the material, including on theinner treatment surface of the tray or strip, can also act as ableaching agent destabilizer, acting to produce free radicals from theperoxide bleaching agent upon contact of the barrier layer with aperoxide bleaching composition. Although platinum is a less preferreddestabilizer because of its generally higher cost, it is within thescope of the present invention to utilize platinum when present. As theplatinum and/or tin may be included in small, silicone-catalyzingamounts (e.g., typically less than 1000 ppm, more typically less than100 ppm), it may be advantageous to include an additional, morepreferred destabilizer, for example magnesium and/or iron in addition tothe residual platinum and/or tin, in order to boost the overalldestabilizing effect.

Styrene-ethylene-butylene-styrene (SEBS), and/or VERSAflex, aproprietary thermoplastic elastomer alloy exhibiting elasticity andother properties similar to silicone, are examples of silicone-likematerials. A suitable example of a SEBS material is SEBS TPE 45A,available from various providers. Physical properties for SEBS TPE 45Aare summarized in the table below. Various other SEBS products may alsobe used in forming a polymeric moisture resistant barrier layer.

Property Value Density (g/cm³) 0.94 Surface Hardness-Shore A 45 TensileStrength (MPa) 6 Flexural Modulus (GPa) 0.02 Notched Izod (kJ/m) 1.06+Linear Expansion (/° C. × 10⁻⁵) 16 Elongation at Break (%) 800 WaterAbsorption (%) 0.3 Oxygen Index (%) 19 Melting Temp. Range (° C.)200-240 Mold Shrinkage (%) 1.5 Mold Temp. Range (° C.) 50-70

Several suitable VERSAFLEX TPE materials are available from GLSCorporation, located in McHenry, Ill. Preferred VERSAFLEX materialsinclude VERSAFLEX CL30 and VERSAFLEX CL40, properties of each of whichare summarized in the table below. Various other VERSAFLEX products fromGLS Corporation can also be used,

Product Property CL30 CL40 Test Method Shore A Hardness, 10 sec delay 3043 ASTM D2240 Specific Gravity 0.89 0.89 ASTM D792, 23/23° C. TensileStrength 6619 kPa 5929 kPa ASTM D412-Die C, 2 hrs, 23° C. Elongation atBreak 780% 690% ASTM D412-Die C, 2 hrs, 23° C. 100% Modulus  689 kPa1379 kPa ASTM D412-Die C, 2 hrs, 23° C. 300% Modulus 1448 kPa 2413 kPaASTM D412-Die C, 2 hrs, 23° C. Tear Strength 19 kN/m 23 kN/m ASTM D624Melt Flow Rate @ 190° C., 2160 g  18 g/10 min 13 g/10 mm ASTM D 1238Melt Flow Rate @ 200° C., 5000 g 108 g/10 min 38 g/10 mm ASTM D 1238Apparent Viscosity @ 200° C. 11170/sec 15 Pa-s 16 Pa-s ASTM D 3835Compression Set, 22 hrs @ RT  11%  12% ASTM D 395B

The silicone or silicone like dental trays are characterized by wallthicknesses of no more than about 1 mm, more preferably between about0.03 mm and about 1 mm, and most preferably between about 0.1 mm andabout 0.5 mm. Wall thicknesses greater than about 1 mm are significantlyless useful as a comfortable dental bleaching tray, as the thickness ofthe tray begins to seriously interfere with the normal relaxed positionof the occlusal tooth surfaces when wearing such a tray (i.e., thetray(s) get in the way between teeth of opposite dental arches,preventing the user from completely closing their jaw), making the traysignificantly less comfortable than a tray with wall thicknesses thatare no more than about 1 mm. For this same reason, existing mouth guardsformed of silicone have little or no use as a comfortable dentaltreatment tray as their wall thickness is typically greater than 2 mm,and more typically about 4 mm so as to provide a cushioning effect tothe teeth when accepting a blow to the mouth or jaw. Similarly, theinventive dental bleaching trays would be unacceptable for use as amouth guard, as their thin walls provide little or no protection to theteeth against such blows.

The durometer hardness/softness of the silicone or silicone like traymaterial is selected so as to strike a balance between softness and wallthickness. Within the preferred wall thicknesses described above (i.e.,about 0.03 mm to about 1 mm) the shore A durometer hardness value willpreferably range from about 90 to about 20. Generally, higher durometervalues (less soft) are preferred with thinner wall trays, while lowerdurometer values (greater softness) are preferred with thicker walltrays. For example, a tray with a wall thickness of about 0.5 mm mayhave a shore A durometer hardness value of about 30, a tray with a wallthickness of about 0.25 mm may advantageously have a shore A durometerhardness value of about 40, while a tray with a wall thickness of about0.1 mm may have a shore A durometer hardness value of about 70. Typicalpreferred shore A durometer hardness values range from about 30 to about70, more preferably from about 40 to about 60. In the case of strips,durometer hardness values and preferred thicknesses are similar to thevalues described above with respect to trays.

The elasticity of the silicone or silicone like tray material is muchgreater than elasticity of thermoplastic materials (e.g., EVA and/or PP)commonly used in forming trays and strips. For both trays and strips,elasticity (also referred to herein as elongation) of the selectedmaterial will preferably range from about 2% to about 2000%, morepreferably from about 100% to about 1000%, more preferably from about300% to about 800%. In addition, elasticity will preferably be no lessthan about 2%, more preferably no less than about 4%, more preferably noless than about 10%, and most preferably no less than about 25%.

The dental treatment trays according to the invention can bemanufactured by injection molding an uncured two-part liquid siliconecomposition into a mold cavity. In the case of liquid silicone rubber,the two parts are of relatively low viscosity (e.g., 1500-2000 Pa-s),which is significantly lower than the viscosity of thermoplasticmaterials traditionally used in molding a dental tray or strip. As such,the injection pressures at which the material is injected into the moldare significantly lower (e.g., about 500 to about 5000 psi, typicallyabout 2000 psi) than encountered when injection molding dental traysfrom EVA, PCL, PVC, and other thermoplastic materials that have beenused in injection molding dental trays or strips (e.g., which aretypically injected at a pressure of about 20,000 psi). Injection moldingwith silicone is more easily and inexpensively accomplished relative tothe difficulty of molding with more common thermoplastic polymermaterials because such trays must be molded with relatively thin wallsto achieve an acceptable degree of comfort for the user. For example,plasticizers must be added to increase the melt flow index of thematerial in order to better fill the entire mold cavity, which is narrowbecause the manufactured tray must be thin-walled for comfort. It mayalso be possible to mold the trays from a high consistency siliconematerial, which is much thicker (e.g., similar to silly putty), andwhich would require greater manufacturing pressures.

Although it is also possible to form silicone or silicone like dentaltrays with comparably thin walls (which may have the greatest comfort),this is not always necessary because a silicone or silicone like dentaltray of a given thickness exhibits comfort greater than a similarlysized dental tray formed of more common thermoplastic materials (e.g.,EVA and PP). As such, a silicone or silicone like tray exhibitingcomfort equal to or better than existing trays may have a wall thicknesswhich is significantly greater than the more common thermoplastic tray.In effect, the use of silicone or a silicone like material allows achoice between a relatively thicker wall dental tray which is moreeasily and inexpensively formed, and which also may not require an outersupport tray during placement, or a thin-wall silicone/silicone likedental tray which provides a degree of comfort not found in a comparabletray formed of another material as a result of its thinness,adaptability, flexibility, elasticity, resiliency, and its soft andsupple feel.

The dental treatment trays according to the invention can be designed tobe worn for any desired time period. Due to the extremely comfortablefit between the inventive dental treatment trays and the person's teeth,it is possible to wear such trays for extended periods of time asdesired. The dental treatment trays can be worn for as little as a fewminutes or as long as several hours. By way of example, not limitation,a typical treatment session of fast duration may last from about 10 toabout 30 minutes; a treatment session of intermediate duration may lastfrom about 30 minutes to about 2 hours; and a treatment session of longduration, including overnight treatment while a person is sleeping, maylast from about 2 hours to about 12 hours.

When used in combination with a sticky treatment composition, dentaltreatment trays may possibly be worn while performing normal dailyactivities, such as talking, drinking, smoking, coughing, smiling,frowning, grimacing, or while sleeping. Dental treatment trays accordingto the invention may be worn over a person's upper dental arch, lowerdental arch, or both simultaneously. Although trays provide an improvedfit as compared to strips that allow treatment as described above, it isof course within the scope of the invention to provide dental treatmentstrips which can also be used to provide similar treatment. Such stripsmay be expected to be worn for similar ranges of time as describedabove, and when used with an initially dry treatment composition thatbecomes very sticky upon contact with water, may even be worn whileengaging in the above described activities as the treatment composition(e.g., a substantially dry treatment composition) more effectively holdsthe strip in place against the tooth tissues to be bleached.

FIG. 6A illustrates a person 375 placing a dental treatment assembly 355over the person's upper dental arch. The outer support tray helps inplacing the inner treatment tray over the teeth. FIG. 6B illustrates adental treatment tray 300 in place over the person's upper dental archand a dental treatment tray 300′ over the lower dental arch, both outersupport trays having been removed.

To remove the dental treatment tray after a desired time period, theuser simply grasps a corner or portion of the tray and pulls it off theteeth. Any residual treatment composition that remains adhered to theperson's teeth can be removed by washing or flushing with water and/orby brushing.

EXAMPLES OF THE PREFERRED EMBODIMENTS

Following are examples of two-part silicone compositions and alternativesilicone like TPE compositions that may be used to manufacture dentaltreatment trays according to the invention by injection molding. Theexemplary formulations and manufacturing conditions are given by way ofexample, and not by limitation. Unless otherwise indicated, allpercentages are by weight.

Example 1

A composition for injection molding a silicone dental treatment tray wasformed from Shin-Etsu's KEG2000-50A/B two part thermoset siliconematerial. Part A containing the activator/hardener had a viscosity ofabout 1700 Pa-s, while part B containing the siloxane had a viscosity ofabout 1600 Pa-s. At least one part included a platinum catalyst.

The two parts of the silicone composition were pumped out of storagedrums through hoses to a static mixing head where the two parts weremixed together. The mixed silicone material exits the static mixer andwas forced into the screw and barrel of the injection molding machine.The mixed silicone material was injected into the heated mold (e.g.,about 375° F.), at which point the material quickly polymerized. Thetray was removed from the hot mold after polymerization wassubstantially complete. Exemplary formed trays exhibited excellentadaptability, flexibility, elasticity, and softness, while also beingresilient. The molded trays were translucent, had a Shore A durometerhardness of about 50, an elasticity of about 580%. Trays having wallthicknesses of about 0.004 inch (0.10 mm), 0.006 inch (0.15 mm), 0.008inch (0.2 mm), 0.01 inch (0.25 mm) and 0.014 inch (0.36 mm),respectively, were formed. The trays were found to be very comfortablewhen worn over a person's dental arch, with better adaptability,flexibility, elasticity, softness, and resiliency as compared to a trayformed of EVA and/or PP. In addition, the silicone material surfaceexhibited a tendency to adhere (i.e., grip) to tooth surfaces.

It is believed that the residual platinum catalyst content within thefinished tray was less than 1000 ppm, more likely less than 100 ppm. Thepresence of residual platinum catalyst within the silicone materialprovided available platinum ions to act as a bleaching agentdestabilizer when contacted with a peroxide dental bleaching agent.

Example 2

A composition for injection molding a dental treatment tray was formedfrom SEBS TPE 45A material. The heated material was pumped so as to beforced into the screw and barrel of the injection molding machine. Thematerial was injected into the mold. The cooled tray was removed fromthe mold. Exemplary formed SEBS trays exhibited excellent adaptability,flexibility, elasticity, and softness, while also being resilient,similar to the silicone tray of Example 1. The molded trays weretranslucent, had a Shore A durometer hardness of about 45, an elasticityof about 800% and a wall thickness of about 0.020 inch (0.5 mm). Thetrays were found to be very comfortable when worn over a person's dentalarch, with better adaptability, flexibility, elasticity, softness, andresiliency as compared to a tray formed of EVA and/or PP. In addition,the SEBS material surface exhibited a tendency to adhere (i.e., grip) totooth surfaces. A bleaching agent destabilizer (e.g., about 0.1 percentto about 5 percent by weight) may be compounded with the SEBS materialprior to molding so that the finished trays include the bleaching agentdestabilizer on the inner surface of the tray.

A composition for injection molding a dental treatment tray is formedfrom VERSAFLEX CL30. The heated TPE material is pumped so as to beforced into the screw and barrel of the injection molding machine. Thematerial is injected into the mold. The cooled tray is removed from themold. Exemplary formed VERSAFLEX CL30 trays exhibit excellentadaptability, flexibility, elasticity, and softness, while also beingresilient, similar to the silicone tray of Example 1. The molded traysare translucent, have a Shore A durometer hardness of about 30, anelasticity of about 780% and a wall thickness of about 0.020 inch (0.5mm). The trays are very comfortable when worn over a person's dentalarch, with excellent adaptability, flexibility, elasticity, softness,and resiliency as compared to a tray formed of EVA and/or PP. Inaddition, the VERSAFLEX CL30 material surface exhibits a tendency toadhere (i.e., grip) to tooth surfaces. A bleaching agent destabilizer(e.g., about 0.1 percent to about 5 percent by weight) may be compoundedwith the VERSAFLEX material prior to molding so that the finished traysinclude the bleaching agent destabilizer on the inner surface of thetray.

Example 4

A composition for injection molding a dental treatment tray is formedfrom VERSAFLEX CL40. The heated TPE material is pumped so as to beforced into the screw and barrel of the injection molding machine. Thematerial is injected into the mold. The cooled tray is removed from themold. Exemplary formed VERSAFLEX CL40 trays exhibit excellentadaptability, flexibility, elasticity, and softness, while also beingresilient, similar to the silicone tray of Example 1. The molded traysare translucent, have a Shore A durometer hardness of about 40, anelasticity of about 690% and a wall thickness of about 0.020 inch (0.5mm). The trays are very comfortable when worn over a person's dentalarch, with excellent adaptability, flexibility, elasticity, softness,and resiliency as compared to a tray formed of EVA and/or PP. Inaddition, the VERSAFLEX CL40 material surface exhibits a tendency toadhere (i.e., grip) to tooth surfaces. A bleaching agent destabilizer(e.g., about 0.1 percent to about 5 percent by weight) may be compoundedwith the VERSAFLEX material prior to molding so that the finished traysinclude the bleaching agent destabilizer on the inner surface of thetray.

Following are examples of dental treatment compositions that can be usedin combination with silicone or silicone like dental treatment trays orstrips of the invention.

Example 5

An initially flowable composition suitable for use in manufacturing asubstantially solid treatment composition was formed by mixing togetherthe following components:

Ethanol 31.95% Water   10% Polyvinyl Pyrrolidone (M.W. = 1.3 million)  27% Polyvinyl Pyrrolidone (M.W. of about 60,000)   10% Sodium LaurelSulfate  0.5% Glycerine   15% Sucralose 25% solution  0.5% Peach Flavor   4% Potassium Nitrate  0.8% Sodium Fluoride  0.25%

The resulting composition is spread over the surface of a pre-moldedsilicone or silicone like dental tray or strip and then dried so as toform a substantially solid treatment composition. The treatmentcomposition is initially dry to the touch, but became very sticky whencontacted with water or saliva during use. The potassium nitrateprovides a dental desensitizing effect. The sodium fluoride providesboth a desensitizing and remineralizing effect. The trays and stripsreliably adhere to tooth tissue, and exhibit excellent comfort andadhesiveness.

Example 6

A sticky, viscous dental bleaching composition was prepared by mixingtogether the following components:

Water 22.5% EDTA Disodium  0.1% Carbamide Peroxide 18.5% Sucralose 25%solution 0.75% Glycerine 41.6% Carbopol 974  5.3% Sodium Hydroxide 50%solution 2.25% Polyvinyl Pyrrolidone (M.W. = 1.3 million)   2%Carboxymethyl Cellulose   4% Watermelon Flavor   3%

All fractions are by weight. A bite ruptureable membrane is positionedadjacent the inner treatment surface of a tray shaped or strip shapedbarrier layer. A bead of dental bleaching composition is then spreadalong the ruptureable barrier layer adjacent the dental bleaching tray.The bleaching composition may be positioned adjacent the labial-buccalwall of the tray, as illustrated in FIG. 5. In the case of a strip, thedental bleaching composition is applied evenly over one side of thestrip shaped barrier layer, with the rupturable membrane between thecomposition and the barrier layer. During placement and/or use therupturable membrane is broken, contacting the composition to the barrierlayer. Upon contact of the bleaching composition with the barrier layer,the peroxide dental bleaching agent is destabilized so as to accelerateproduction of free radicals. The trays and strips reliably adhere totooth tissue, and exhibit excellent comfort and adhesiveness.

Additional exemplary dental treatment compositions, and methods formaking such compositions, which may be used with devices according tothe invention are disclosed in U.S. Pat. No. 5,376,006; U.S. Pat. No.5,785,527; U.S. Pat. No. 5,851,512; U.S. Pat. No. 5,858,332; U.S. Pat.No. 5,985,249; U.S. Pat. No. 6,306,370; U.S. Pat. No. 6,309,625; U.S.Pat. No. 6,312,671; U.S. Pat. No. 6,322,774; U.S. Pat. No. 6,368,576;U.S. Pat. No. 6,387,353; U.S. Pat. No. 6,500,408; U.S. Pat. No.6,503,485 and U.S. patent application Ser. No. 11/460,016 filed Jul. 26,2006. For purposes of disclosing dental treatment compositions, andmethods of making such compositions, the foregoing patents andapplication are incorporated herein by reference.

The present invention may be embodied in other specific forms withoutdeparting from its spirit or essential characteristics. The describedembodiments are to be considered in all respects only as illustrativeand not restrictive. The scope of the invention is, therefore, indicatedby the appended claims rather than by the foregoing description. Allchanges which come within the meaning and range of equivalency of theclaims are to be embraced within their scope.

What is claimed is:
 1. A non-customized dental treatment tray,comprising: a barrier layer formed from an elastomeric material in theshape of a dental tray, wherein the barrier layer is devoid ofstructures corresponding to a size and shape of a person's uniquedentition, wherein the elastomeric material comprises a non-silicone,silicone-like thermoplastic elastomer having an elastic elongation of atleast 25%, and wherein the barrier layer has a thickness of less thanabout 1.5 mm.
 2. A non-customized dental treatment tray as in claim 1,wherein the non-silicone, silicone-like thermoplastic elastomercomprises styrene-ethylene-butylene-styrene thermoplastic elastomer. 3.A non-customized dental treatment tray as in claim 1, wherein thenon-silicone, silicone-like thermoplastic elastomer is a thermoplasticelastomer alloy.
 4. A non-customized dental treatment tray as in claim1, wherein the non-silicone, silicone-like thermoplastic elastomer hasan elastic elongation in a range of about 100% to about 1000%.
 5. Anon-customized dental treatment tray as in claim 1, wherein thenon-silicone, silicone-like thermoplastic elastomer has an elasticelongation in a range of about 300% to about 800%.
 6. A non-customizeddental treatment tray as in claim 1, wherein the barrier layer consistsessentially of the non-silicone, silicone-like thermoplastic elastomer.7. A non-customized dental treatment tray as in claim 1, wherein thenon-customized barrier layer has a thickness of less than about 1 mm. 8.A non-customized dental treatment tray as in claim 1, wherein thenon-customized barrier layer has a thickness of less than about 0.5 mm.9. A non-customized dental treatment tray as in claim 1, wherein thenon-silicone, silicone-like thermoplastic elastomer is blended with atleast one auxiliary component selected from the group consisting ofelastomers, latexes, water, plasticizers, and nitriles.
 10. Anon-customized dental treatment tray as in claim 9, wherein the at leastone auxiliary component is included in an amount of more than 0% and upto about 10% by weight.
 11. A non-customized dental treatment tray as inclaim 1, wherein barrier layer is soft, flexible and elasticallydeformable in order to be highly adaptable so that, when placed over aperson's teeth during use, the non-customized barrier layer adapts andat least partially conforms to the person's teeth.
 12. A non-customizeddental treatment tray, comprising: a barrier layer formed from anelastomeric material in the shape of a dental tray, wherein the barrierlayer is devoid of structures corresponding to a size and shape of aperson's unique dentition, wherein the elastomeric material comprises anon-silicone, silicone-like thermoplastic elastomer having an elasticelongation of at least 25%, and wherein the elastomeric material cannotbe sufficiently softened by boiling in water to form a customized dentaltray.
 13. A non-customized dental treatment tray as in claim 12, whereinthe non-silicone, silicone-like thermoplastic elastomer comprisesstyrene-ethylene-butylene-styrene thermoplastic elastomer.
 14. Anon-customized dental treatment tray as in claim 12, wherein thenon-silicone, silicone-like thermoplastic elastomer is a thermoplasticelastomer alloy.
 15. A non-customized dental treatment tray as in claim12, wherein the non-silicone, silicone-like thermoplastic elastomer hasan elastic elongation in a range of about 100% to about 1000%.
 16. Anon-customized dental treatment tray as in claim 12, wherein thenon-silicone, silicone-like thermoplastic elastomer has an elasticelongation in a range of about 300% to about 800%.
 17. A non-customizeddental treatment tray, comprising: a barrier layer formed from anelastomeric material in the shape of a dental tray, wherein the barrierlayer is devoid of structures corresponding to a size and shape of aperson's unique dentition and has a thickness of less than about 1.5 mm,wherein the elastomeric material comprises a non-silicone, silicone-likethermoplastic elastomer having an elastic elongation of at least 25%,and wherein the elastomeric material cannot be sufficiently softened byboiling in water to form a customized dental tray.
 18. A non-customizeddental treatment tray as in claim 17, wherein the non-silicone,silicone-like thermoplastic elastomer is a thermoplastic elastomeralloy.
 19. A non-customized dental treatment tray as in claim 17,wherein the non-silicone, silicone-like thermoplastic elastomer has anelastic elongation in a range of about 100% to about 1000%.
 20. Anon-customized dental treatment tray as in claim 17, wherein thenon-silicone, silicone-like thermoplastic elastomer has an elasticelongation in a range of about 300% to about 800%.